2012/1/25 Mathieu Blondel <[email protected]>: > On Thu, Jan 26, 2012 at 12:40 AM, Paolo Losi <[email protected]> wrote: > >> do you see any use case for which distance calculation is >> performed in an "outer" loop? > > In my case, the pairwise matrix is an argument to the learning > algorithm and is computed once for all in the beginning. So, I really > want it do be as fast as possible. Also, I think the code I added is > reasonably easy to understand and maintain. > > My intuition was also that the low-level blas functions would be > parallelized so I was surprised by the speed gain when using n_jobs. > (My blas and atlas are coming from the Ubuntu packages.)
That explains why: the last time I checked the Ubuntu packages for atlas they did not look as if they were compiled with multi-threading support enabled. I think the simplest way to get atlas with multi threading support under ubuntu is debootsrap the debian unstable packages and leave the autotuning build of atlas do its magic. Still I find it a good idea to have an explicit API to perform kernel precomputation in parallel on multicore rather than hoping that the underlying runtime will do it automatically (which is not the case for 99% of the ubuntu and windows users). -- Olivier http://twitter.com/ogrisel - http://github.com/ogrisel ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Scikit-learn-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/scikit-learn-general
